Hi Al - My first shot at a parametric isogrid. I usually do this in Rhino but then its hard to adjust, In fact every iteration has to be rebuilt entirely. That's why I should get into Grasshopper. The prior semicircular solution weighs 19.77kg and this weighs 11.95kg nearly half. It deflects 0.36mm vs the 0.12mm of our best so far, poor result. But its an attempt. The grillage should be behind the rails.but I couldn't figure out how to do that parametrically. I built this as two counter helixes and some longitudinals. I'll have another crack soon. My thoughts are I can have a tube laser cut with all the holes, but then I'm choosing the solution based on manufacture. I can 3D print nearly anything so shouldn't consider manufacture yet. Peter

this should be in the other thread